Abstract
The discovery of bio-molecules in meteorites with an excess of one chiral state has created one of the biggest questions in astrobiology today. That is, what is the origin of bio-molecular homochirality? Studies of this question are highly interdisciplinary, and while several phenomenological models exist, we examine the relationship between fundamental symmetries at the particle level and the macroscopic formation of bio-molecules. A model has been developed which couples fundamental interactions with the formation of molecular chirality. In this magneto-chiral model atomic nuclei bound in amino acids interact via the weak interaction in stellar environments. Nuclei are coupled to the molecular geometry (chirality) via the shielding tensor, the same interaction responsible for NMR identification. Associated with this is the fact that isotopic abundances vary from solar system values. Interactions with leptons can selectively destroy one chiral state over the other while changing isotopic values. Possible sites are proposed in which this model may exist.
Highlights
Because they are asymmetric, amino acids have two chiral states - or mirror images - referred to as “left-handed” and “right-handed” forms, prefixed with L- and D- respectively
After selection of a particular chirality within a meteorite, successive synthesis or evolution of the molecules via autocatalysis can amplify this enantiomeric excess [6], which is defined to be the relative difference in numbers of left and right handed enantiomers; ee = (NL − NR)/(NL + NR)
The primary goal of the work presented here is to explore the fundamental physics involved in the origin of biomolecular homochirality and to answer the question, Is there a nuclear physics origin of biomolecular homochirality?
Summary
Amino acids have two chiral states - or mirror images - referred to as “left-handed” and “right-handed” forms, prefixed with L- and D- respectively. It may be possible that non-zero ees in meteorites may have influenced terrestrial homochirality. The excess left-handed amino acids within these meteorites could influence the ees of existing amino acid populations on the earth and be amplified via terrestrial autocatalytic mechanisms [19, 20]. A large segment of astrobiological exploration today is focused on locating and quantifying amino acids in stellar environments. This includes astronomical observations and theory [30, 39,40,41] as well as space missions to search for amino acids in comets and asteroids [42, 43]. The primary goal of the work presented here is to explore the fundamental physics involved in the origin of biomolecular homochirality and to answer the question, Is there a nuclear physics origin of biomolecular homochirality?
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